of its natural history, I ought in the first place to state that I
have not had the opportunity of reading or studying the great original
treatise of Professor Salisbury. I am acquainted with it only through a
resume published in the _American Journal of the Medical Sciences_
for the year 1866, new series, vol. li. p. 51. At the beginning of my
investigations I was engaged in a microscopic examination of the water
and mud of swampy shores and of the marshes, also with a comparison of
their microphytes with those which might exist in the urine of patients
affected with intermittent fevers. Nearly three months passed without
my being able to find the least agreement, the least connection. Having
lost nearly all hope of being able to attain the end which I had
proposed, I took some of the slime from the marshes and from the masses
of kelp and Confervae from the sea shores, where intermittent fevers are
endemic, and placed them in saucers under the ordinary glass desiccators
exposed on a balcony, open for twenty-four hours, the most of the time
under the action of the burning rays of the sun. With the evaporated
water deposited within the desiccators, I proceeded to an examination,
drop by drop. I at length found that which I had sought so long, but
always in vain.

The parasite of intermittent fever, which I have termed Limnophysalis
hyalina, and which has been observed before me by Drs. J. Lemaire and
Gratiolet (_Comptes Rendus Hebdomadaires de l'Academie des Sciences_,
Paris, 1867, pp. 317 and 318) and B. Cauvet (_Archives de Medecine
Navale_, November, 1876), is a fungus which is developed directly
from the mycelium, each individual of which possesses one or several
filaments, which are simple or dichotomous, with double outlines,
extremely fine, plainly marked, hyaline, and pointed. Under favorable
conditions, that is, with moisture, heat, and the presence of vegetable
matter in decomposition, the filaments of mycelium increase in length.